Researchers at the Swiss Federal Institute of Technology have successfully allowed paralyzed monkeys to walk again with the use of a brain implant. It is the first time scientists have been able to restore walking ability in paralyzed primates, raising hopes for new treatments for people with debilitating spinal injuries. The technology could help restore such patient’s ability to walk. By sending movement signals from the brain to electrodes in the spine, that would then activate leg muscles. Researchers were able to restore the ability to walk to a rhesus macaque who had been partially paralyzed in a surgical procedure just six days earlier. The procedure severed nerves that controlled his right hind leg. The macaque regained the ability to walk after being fitted with the implant.
“It was a big surprise for us,” said Grégoire Courtine, a neuroscientist and the head researcher. “The gait was not perfect, but it was almost like normal walking. The foot was not dragging and it was fully weight bearing.”
In a paralyzing spinal cord injury, movement signals from the brain are interrupted if the spinal cord is broken. Implants such as the one used by the researchers are placed in the motor cortex, which is the movement center of the brain. The implants record activity there and wirelessly send the signals to a computer, which then decodes motor intention and sends instructions to a pulse generator placed on the other side of the lesion in the spinal cord. By connecting the brain to working nerves that control the right leg, the patient – in this case, the macaque, is able to walk again.
The researchers also fitted the device to an animal with more serious damage to the nerves in its leg. According to the research, which was published in the journal Nature, that animal regained the ability to walk two weeks after the device was implanted.
This success with “brain-spine interface” adds to a number of recent breakthroughs in the field of neuroprosthetics, in which scientists uses technology to read intentions in the brain to control robotic arms and even paralyzed limbs.
While Courtine says he does not foresee full restoration of leg movement in the near future, scientists are optimistic that it could help patients with spinal cord injuries in which the spine is not completely severed.
Meanwhile, a new feasibility study at Lausanne University Hospital in Switzerland is testing the therapeutic capability of the spine part of the interface in patients with spinal cord injuries. A neurosurgeon at the hospital, Jocelyne Bloch, said “For the first time, I can imagine a completely paralysed patient able to move their legs through this brain-spine interface.”